The present disclosure relates to a vector modulator, and more particularly to a vector modulator configured to modulate magnitude and phase of an input signal by modulating a phase of I/Q channel signal, using time delay and phase shifter.
A vector modulator is a device employed by a calibrator and an amplifier for simultaneously controlling magnitude and phase of a signal. The vector modulator generally receives an input signal and outputs the signal by splitting it into In-phase (I) channel signal and quadrature (Q) channel signal having a particular phase. To this end, the input signal is converted into an I channel signal having a phase difference of 90° and a Q channel signal, where the I/Q signal is outputted in response to an outside control signal with each magnitude unchanged but with changed phase. The outputted signal is attenuated by an amplitude variable attenuator at a predetermined attenuation ratio and outputted with a vector sum thereof.
However, the prior art vector modulator makes four quadrant signals comprising a polar coordinate system, variably controls each amplitude of each quadrant signal using an amplitude variable attenuator, couples the same with the vector sum and output. Under the circumstances, the prior art vector modulator must be disadvantageously formed with an amplitude variable attenuator to complicate the circuit configuration.
Another disadvantage is that there is a cumbersomeness of converting each I/Q signal to amplitude control value in order to obtain an arbitrary phase angle for using the amplitude variable attenuator. Still another disadvantage is that there is a cumbersomeness of going through a complicated process for obtaining a phase angle outputted by a final vector sum.